Graphics design

Hi,
I am a programmer and I have to learn drawing graphics or images for games may be using photoshop. I could visualize what to make but when I try to make it in photoshop I could not make good looking like of some games available in ipad HD or iphone hd games. can anyone suggest some tutorials or tips for making such HD good looking graphics. I tryied searching but could not find any thing useful.
Thanks a lot.

Practice, practice, practice. I know that may sound impractical as telling a fat person to exercise to lose weight, but it works! I promise. And most importantly, test all of your artwork on the platform you wish to visualize it on. It's not enough if it looks good in front of you.

Lastly, get critiqued on places such as deviantart, or other art forums. There is no limit to the amount of people who want to critique things.

thanks skyhawk and AndyKorth for the help. yes it will need lot of practice but it will better if we know where to put our effort than it will be best. Thanks for the links, i will start from these link to see the basics and search related items. Any other such useful links will be very helpful.
thanks a lot.

You have to remember also, that many of these designers are just that only designers, it is their life
Try deconstruct the artwork you see recreate things and learn in the process how to put it back together, then try apply these techniques to your own artwork.

I've found that a vector art program is very useful. They typically come with built-in themes that you can use or deconstruct, and shapes that you can use or adapt. Well-suited to experimentation, and it's not a big deal if you suddenly have to regenerate your artwork at a higher resolution, or come up with an oddball resolution icon for a particular platform or website.

I've had fun and gotten good results with Art Text 2, currently $20 on the Mac App Store. (Demo available on the publisher's website.) There are alternatives but I don't have personal experience with them.